The Local Peer Discovery protocol, specified as BEP-14, is an extension to the

BitTorrent BitTorrent is a Protocol (computing), communication protocol for peer-to-peer file sharing (P2P), which enables users to distribute data and electronic files over the Internet in a Decentralised system, decentralized manner. The protocol is d ...

file-distribution system. It is designed to support the discovery of local

peers, aiming to minimize the traffic through the

Internet service provider An Internet service provider (ISP) is an organization that provides a myriad of services related to accessing, using, managing, or participating in the Internet. ISPs can be organized in various forms, such as commercial, community-owned, no ...

's (ISP) channel and maximize use of higher-

bandwidth Bandwidth commonly refers to: * Bandwidth (signal processing) or ''analog bandwidth'', ''frequency bandwidth'', or ''radio bandwidth'', a measure of the width of a frequency range * Bandwidth (computing), the rate of data transfer, bit rate or thr ...

local area network A local area network (LAN) is a computer network that interconnects computers within a limited area such as a residence, campus, or building, and has its network equipment and interconnects locally managed. LANs facilitate the distribution of da ...

s (LANs). Local Peer Discovery is implemented with

HTTP HTTP (Hypertext Transfer Protocol) is an application layer protocol in the Internet protocol suite model for distributed, collaborative, hypermedia information systems. HTTP is the foundation of data communication for the World Wide Web, wher ...

-like messages on

User Datagram Protocol In computer networking, the User Datagram Protocol (UDP) is one of the core communication protocols of the Internet protocol suite used to send messages (transported as datagrams in Network packet, packets) to other hosts on an Internet Protoco ...

(UDP)

multicast In computer networking, multicast is a type of group communication where data transmission is addressed to a group of destination computers simultaneously. Multicast can be one-to-many or many-to-many distribution. Multicast differs from ph ...

group 239.192.152.143:6771 (

IPv4 Internet Protocol version 4 (IPv4) is the first version of the Internet Protocol (IP) as a standalone specification. It is one of the core protocols of standards-based internetworking methods in the Internet and other packet-switched networks. ...

) or ff15::efc0:988f (

IPv6 Internet Protocol version 6 (IPv6) is the most recent version of the Internet Protocol (IP), the communication protocol, communications protocol that provides an identification and location system for computers on networks and routes traffic ...

) which are administratively scoped multicast addresses. It's similar to

Simple Service Discovery Protocol The Simple Service Discovery Protocol (SSDP) is a network protocol based on the Internet protocol suite for advertisement and discovery of network services and presence information. It accomplishes this without assistance of server-based configu ...

but sends BT-SEARCH instead of M-SEARCH: BT-SEARCH * HTTP/1.1\r\n Host: \r\n Port: \r\n Infohash: \r\n cookie: \r\n \r\n \r\n Since implementation is simple, Local Peer Discovery is implemented in several clients (

μTorrent μTorrent, or uTorrent (see pronunciation), is a proprietary adware BitTorrent client owned and developed by Rainberry, Inc. The " μ" (Greek letter " mu") in its name comes from the SI prefix "micro-", referring to the program's small memo ...

, BitTorrent/Mainline, MonoTorrent,

libtorrent libtorrent is an open-source implementation of the BitTorrent protocol. It is written in and has its main library interface in C++. Its most notable features are support for Mainline DHT, IPv6, HTTP seeds and μTorrent's peer exchange. libtor ...

and its derivatives,

Transmission Transmission or transmit may refer to: Science and technology * Power transmission ** Electric power transmission ** Transmission (mechanical device), technology that allows controlled application of power *** Automatic transmission *** Manual tra ...

, aria2). An alternative multicast peer discovery protocol based on

ZeroConf Zero-configuration networking (zeroconf) is a set of technologies that automatically creates a usable computer network based on the Internet Protocol Suite (TCP/IP) when computers or network peripherals are interconnected. It does not require manu ...

is published a
BEP 26 Zeroconf Peer Advertising and Discovery
but is not widely adopted since it is considered too complex in comparison.

References

BitTorrent Network protocols {{Compu-network-stub